At the country level, ETFs tracking developing nations ranging from Colombia to Mexico to the Philippines to Thailand to Poland and scores of others have impressed as well.

That all sounds good, but it does not mean all emerging markets ETFs have delivered for investors in 2012. Some have been downright disappointments, including marquee emerging markets ETFs such as the iShares MSCI Brazil Index Fund (NYSE: EWZ).

To be sure, disappointment comes in a variety of forms and EWZ has been not the only emerging markets ETF turkey this year. Some of the following funds have been just equally, if not more, disappointing.

Market Vectors Vietnam ETF (NYSE: VNM)
Looking at VNM's year-to-date gain of 16.7 percent could make the ETF's inclusion on this list confusing to the untrained eye. However, a quick glance at VNM's chart shows the bulk of the ETF's gains were accrued in the first quarter and after the fund failed to run much past $21 in May, the ensuing tumble was disheartening.

Coming off a 2011 when Vietnamese stocks were hammered by rampant inflation and currency devaluations, it looked like VNM finally had its act together early this year. That theory would be dispelled. In the third quarter came news of the arrest of two noteworthy Vietnamese banking scions, headlines that dealt a blow to investor confidence in Vietnamese banks.

Investors were harshly reminded this is a corrupt country and headlines about a banking sector awash in bad loans did not help. In other words, Vietnam squandered a great opportunity for itself and VNM this year.

The good news is VNM has shown signs of life in recent weeks. The fund, which tracks a market that is cheap relative to the broader emerging markets universe, has surged 7.7 percent in the past month. Remember, it was in the late fourth quarter of 2011 that VNM started perking up before surging in the early part of the new year. Perhaps a sequel is in store.

Market Vectors Indonesia ETF (NYSE: IDX)
As early as early February, ETFs tracking Indonesia were showing laggard signs and that is exactly what they have been this year. In the case of IDX, the ETF is up almost 2.5 percent year-to-date, but that is nowhere the returns offered by ETFs tracking Malaysia, the Philippines, Thailand and the aforementioned VNM.

There are some cautionary tales regarding the Indonesian economy, Southeast Asia's largest. Like many emerging markets, Indonesia is home to decrepit infrastructure. For now at least, Indonesia is on the India infrastructure plan, which is short on action. Second, there are some signs of a property bubble. The last time Indonesian real estate reached bubble heights was in 1998 right before the Asian financial crisis.

Still, a bull case remains for Indonesia and IDX. The economy is expected to grow 6.4 percent per year from 2013 through 2017, the highest growth rate of the ASEAN nations, according to the Jakarta Post.

PowerShares Golden Dragon China Portfolio (NYSE: PGJ)
The PowerShares Golden Dragon China Portfolio is a disappointment relative to its peer group as the ETF is down almost 5.3 percent this year. That loss is bad on its own, but it looks worse when measured against an almost 13 percent gain for the iShares FTSE China 25 Index Fund (NYSE: FXI), an almost 18 percent jump for the iShares MSCI China Index Fund (NYSE: MCHI) and a 16.2 percent gain for the SPDR S&P China ETF (NYSE: GXC).

What has bitten PGJ is its exposure to small-cap growth names (an allocation of 10.6 percent) and its exposure to Chinese Internet names. For example, Baidu (NASDAQ: BIDU), Sina (NASDAQ: SINA) and NetEase (NASDAQ: NTES) are down an average of 12 percent this year and those three names combine for almost 18 percent of China's weight.

There is hope for PGJ. The Chinese economy is rebounding in earnest and there is something to be said for controversial stocks, of which Chinese Internet names fit the bill. When the darkest clouds have passed, controversial stocks can rally in significant fashion. That means there could be upside in store for PGJ in 2013.